I/O Network Module with Unique Network Address

ABSTRACT

I/O network modules connect field devices to a process control network. Each I/O network module includes a set of electrical connectors for connecting a field device to the module and an I/O channel extending from the set of electrical connectors to a network port. The I/O channel includes a conversion circuit that converts between an I/O signal and network-compatible signals. Each I/O channel connected to the process control network through an I/O network module is associated with its own unique network address. This enables controllers and field devices on the process control network to communicate essentially directly with one another through the network.

RELATED APPLICATION

This application claims priority to and is a continuation of U.S. patentapplication Ser. No. 16/710,733 “I/O Module with Unique Network Address”filed Dec. 11, 2019 at Attorney Docket No. 14-1372 and pending on thefiling date of the instant application, which priority application isincorporated by reference as if fully set forth herein.

BACKGROUND OF THE DISCLOSURE

Process control networks transmit I/O signals to and from field devicesunder the control of a control system that regulates and controlsindustrial processes. Field devices include sensors and actuators.Sensors transmit input signals representing the state of processvariables to the controllers, and actuators receive output signals fromthe controllers and take action to affect process variables.

I/O signals may be analog signals or digital signals. Analog I/O signalsare variable, in which a voltage or current represents the magnitude ofa process parameter such as flow rate or the desired position of avalve. Digital I/O signals represent one of two states: “on/off”,“opened/closed”, and the like.

Other types of digital signals used in process control are used toactuate a relay or to count pulses.

Sophisticated industrial processes may use a number of field devicesdistributed over a wide area for process control. I/O field wiring fromthe field devices is often brought to a central location for ease ofmanagement. The field wiring may extend to sets of terminals of aterminal block contained in a wiring cabinet. A circuit (referred to asan I/O channel herein) extends from each set of terminals and isconnected to a head station to transfer signals between the set ofterminals and the head station.

The head station communicates with the field devices through the I/Ochannels and communicates with the control system through a separatenetwork. The control system communicates with the head station and notdirectly with the individual field devices.

The head station uses a digital data format, typically a proprietarydata format. The I/O channel includes a conversion circuit that convertsbetween the I/O signal format used by the connected field device and thedigital data format required by the head station.

Fixed-mode conversion circuits convert between one type of I/O signaland a digital data format.

Selectable-mode conversion circuits selectively convert betweendifferent types of I/O signals and a digital data format.Selectable-mode conversion circuits allow different types of fielddevices to be connected to a set of terminals of the terminal block.

Brodbeck, et al. U.S. Pat. No. 9,971,727 “Universal I/O SignalInterposer System”, assigned to the applicant and incorporated byreference herein, discloses that removable I/O modules can be insertedor interposed in the I/O channel to process the I/O signals, supplypower to field devices, interpose fuses or other ancillaries in thesignal path, and other functions.

The use of removable I/O modules and selectable-mode conversion circuitsprovides great flexibility in wiring field devices to the wiringcabinet. However, the control system must continue to communicatethrough the head station or to I/O cards of the control system and doesnot communicate directly with field devices.

It is desired to provide increased capability of the control system andfield devices to communicate in a process control network.

SUMMARY OF THE DISCLOSURE

Disclosed are I/O network modules for a digital process control network.An I/O network module includes an I/O channel connected to a networkport that connects the I/O network module to the process controlnetwork. The network port is compatible with the physical layer of theprocess control network and is configured to operate using networkprotocols compatible with the process control network.

Standardized protocols such as TCP/IP, Profinet, UDP, etc. are used inmany process control networks and embodiments of I/O network modules canbe provided for use with different network protocols.

Each I/O channel is associated with its own unique network address. Thenetwork port attaches the I/O network module to the process controlnetwork and enables essentially direct communication between the controlsystem and the field device through the network port and the I/Ochannel. The process control network may also allow direct fielddevice-to-field device communications through the network.

The I/O channel is provided with a conversion circuit that converts thesignal transmitted along the I/O channel between the I/O signal formatused by the field device and a digital data format compatible with theprocess control network. An I/O channel may also include amicroprocessor and other circuit components necessary for its operation,including setting the mode of operation of any selectable-modeconversion circuits.

In embodiments, the conversion circuit is a fixed-mode conversioncircuit operable in only one mode to convert one type of I/O signal. Inother embodiments, the conversion circuit is a selectable-modeconversion circuit that can convert different types of I/O signals. Theoperating mode of the selectable mode conversion circuit can be set bythe control system through the network or set automatically in responseto the type of field device being attached to the I/O channel.

In further possible embodiments, the I/O channel is configured to allowa removable interposer or I/O module to be inserted in the I/O channelto process the I/O signals, supply power to field devices, interposefuses or other ancillaries in the signal path, and the like as describedin the '727 patent, or to provide other functions.

In yet further possible embodiments, the I/O channel and the networkport are configured for connection to a process control networkutilizing a standardized physical layer and network protocol; forexample an Ethernet network using the TCP/IP protocol. The network maybe a wired network using, as a non-limiting example, twisted-pairwiring, or a wireless network, using, for example, wireless Ethernet.The I/O channel may be provided with or otherwise associated with amedia access control address (MAC address) or other addressing protocolthat uniquely identities the network port.

In use in some networks, such as networks complying with the AdvancedPhysical Layer (APL) standard, the disclosed I/O network module allowsfor the bridging between non-intrinsically safe zones (such ascontroller locations) and hazardous zones or explosive zones requiringintrinsic safety.

The I/O network module may be provided as a “dongle” or single-channelI/O network module that includes a set of electrical connectors forconnecting the field wires of a single field device. The set ofelectrical connectors forms part of a single I/O channel extending to anetwork port. The single-channel I/O network module may be insertedadjacent to an existing termination of the field wires of the fielddevice by cutting or otherwise removing the wires from existingterminals and reattaching them to the set of electrical connectors ofthe single-channel module.

The single-channel I/O network module can be reprogrammed or replacedwith another single-channel I/O network module to change the type ofnetwork (for example, from an Ethernet network to a network having adifferent physical layer) or to change the network data format from,say, Ethernet/IP to OPC UA, with no change to the field device and oftenwithout the need to replace the signal wires extending from the fielddevice.

Embodiments of the I/O channel of the single-channel I/O network modulemay be configured to receive a removable interposer or I/O module forsignal processing and the like as previously described.

The single-channel I/O network module associates a network port with asingle field device. In other embodiments a multi-channel I/O networkmodule associates a network port with multiple field devices.

In Ethernet-based embodiments, for example, the I/O network moduleincludes an Ethernet switch disposed in the module so that the networkport can transmit out to the rest of the network and functions to hideother network locations behind it. This enables creation of firewallsand VPNs (Virtual Private Networks) between a controller of the processcontrol network and the field devices of the process control network.Creating a cybersecurity function between the controller and the fielddevices reduces the potential attack vectors for bad actors to accessthe process control network.

The multi-channel I/O network module includes multiple sets ofelectrical connectors configured to connect to respective sets of fieldwires of multiple field devices. The sets of electrical connectors maybe formed, as a non-limiting example, as a terminal block havingmultiple sets of terminals for connecting the field wires to multipleI/O channels, each set of terminals forming part of a respective I/Ochannel. The multiple I/O channels terminate at a signal processingcircuit connected to the network port. The signal processing circuittransfers data received from the I/O channels to the network port anddistributes data received from the network port to the appropriate I/Ochannel.

Each I/O channel may be configured to receive a removable interposer orI/O module as previously described.

One or more single-channel I/O network modules and/or one or moremulti-channel modules may be connected to the process control network.Each I/O channel may be associated with its own unique network addressusing, for example, internet protocols such as IPv4 or IPv6. Embodimentsof the disclosed I/O network module having a single network port mayutilize forthcoming multi-drop Ethernet technology (expected as a comingaddendum to the 802.3.cg standard or potentially a new industry standardon its own).

The process control network may utilize network topologies designed forredundancy and/or security and may include additional network hardwaresuch as switches and hubs that are known in the network art.

Embodiments of the disclosed single-channel or multi-channel I/O networkmodules may include two network ports that allow for daisy chaining ofI/O network modules or I/O network modules and other network devices,and permit use in ring network topologies requiring devices having twonetwork ports for network redundancy.

Other objects and features of the disclosure will become apparent as thedescription proceeds, especially when taken in conjunction with theaccompanying drawing sheets illustrating one or more non-limitingembodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic side view of a single-channel I/O network modulein accordance with this disclosure, shown attached to the field wires ofa field device.

FIG. 2 is a schematic top view of a multi-channel I/O network module inaccordance with the disclosure.

FIG. 3 is a schematic diagram of an Ethernet-based local process controlnetwork formed at least in part by interconnecting single-channel and/ormulti-channel modules.

DETAILED DESCRIPTION

FIG. 1 schematically illustrates a non-limiting embodiment of asingle-channel I/O network module 100 for use with an Ethernet-basedprocess control network. The illustrated single-channel I/O networkmodule connects a set of field wires of a field device D to the processcontrol network utilizing a standard Ethernet-compatible network port.

I/O network modules for wired process control networks having differentphysical layers or wireless process control networks would include adifferent type wired or wireless network port (for example, an M12 ortwo-wire terminal block in the case of T1L networks) compatible with theprocess control network the I/O network module is intended to connectwith. A network port may include a single port to receive/transmit dataor two or more ports to enable daisy chaining or use in single- ordouble-ring network topologies for example.

The single-channel I/O network module 100 includes a base 10 thatincludes a set 12 of one or more electrical connectors formed in theillustrated embodiment as a set of terminals for terminating the set offield wires of the field device, an Ethernet-compatible RJ-45 networkport 14 having an associated MAC address 16 for connecting the I/Onetwork module to an Ethernet network, and an I/O channel 18 connectingthe terminals with the network port. The network port 14 may beconfigured to operate as a managed switch or as an unmanaged switch asdetermined by the network requirements.

A field device may have a set of one or more field wires, and the set ofelectrical connectors that connect the field wires to the I/O networkmodule can be configured to connect different numbers of field wires anddifferent types of field wire terminations.

The illustrated I/O channel 18 includes a selectable-mode conversioncircuit 20 that converts data between the field device I/O signal formatand a digital data protocol (for example, Ethernet/IP or OPC UnitedArchitecture [OPC UA]) used by the control system. Examples ofselectable-mode conversion circuits that can be adapted for use with thedisclosed I/O signal processor include, but are not limited to, thoseprovided by the commercially available ANALOG DEVICES AD74412R orAD74413R signal processing integrated circuits (Analog Devices, Inc.,One Technology Way, Norwood Mass. 02062-9106 USA).

The I/O channel 18 extends through a removable interposer or I/O module22 attached to the base 10 that can pass an I/O signal through a moduleI/O channel portion 18 m unchanged, provide desired signal processing,interpose a fuse or other ancillary, or the like, as described in the'727 patent.

Other embodiments of I/O modules may provide diagnostics of the I/Ochannel during operation; enable pre-commissioning evaluation ofattached field devices prior to normal operation of the process controlnetwork; analog signal scaling functions (for non-limiting examples,signals within a 24V signal range scaled to a 5V signal range, 4-20masignals converted to a voltage signal within a voltage range), or otherfunctions.

Yet other embodiments of the I/O module 22 and the base 10 may outputraw or processed diagnostic information related to the field deviceattached to the I/O channel or to the state or operating history of anancillary in the module I/O channel portion through the network port 14.

A monitoring circuit 24 is disposed between the port 14 and theconversion circuit 20 and is connected to a programming port 26 of theconversion circuit. The monitoring circuit reads and monitors the databeing transferred to and from the port, and can also write data to theport. The monitoring circuit can be powered using Power over Ethernet(POE), a separate power supply (not shown), or other conventionalconfigurations.

The monitoring circuit 24 monitors the data for a command to set theoperating mode of the conversion circuit 20. When such a command isreceived, the monitoring circuit issues a command to the programmingport 26 setting the operating mode of the conversion circuit.

The monitoring circuit 24 also monitors data transmittal for purposes ofsecurity (for example, authentication, authorization, etc.) and networkdiagnostics, and can report security and network diagnostics informationto a controller of the control system through the process controlnetwork.

The monitoring circuit 24 can also assure the conversion circuit 20ignores and does not convert data received from the network port 14intended for use by the monitoring circuit or generated by themonitoring circuit.

FIG. 2 schematically illustrates an embodiment of a multi-channel I/Onetwork module 102. The multi-channel I/O network module is capable ofconnecting multiple field devices to a controller of a process controlnetwork through a network port. The illustrated multi-channel I/Onetwork module connects up to four field devices to the network port(other embodiments could connect more than four or less than four fielddevices).

The illustrated multi-channel I/O network module 102 includes a base 110having multiple sets of electrical connectors formed as a terminal block111 containing four sets 112 of terminals for terminating the fieldwires of up to four field devices (not shown), an RJ-45 network port 114having an associated MAC address 116 for connecting the I/O networkmodule to an Ethernet-based process control network, and a respectiveI/O channel 118 extending from each set of terminals 112 and including aselectable-mode conversion circuit 120 and removable interposer 122. TheI/O channels include in common a monitoring circuit 124 connected to thenetwork port. The monitoring circuit is also connected to a programmingport 126 of each conversion circuit.

The monitoring circuit 124 reads and monitors the data being transferredto and from the port 114, and can also write data to the port. Themonitoring circuit can be powered using Power over Ethernet (POE) orfrom a separate power supply (not shown).

The monitoring circuit 124 monitors the data for a command to set theoperating mode of a conversion circuit 120. When such a command isdetected, the monitoring circuit issues a command to the programmingport 126 of the appropriate conversion circuit, setting the operatingmode of the conversion circuit.

The monitoring circuit 124 also monitors data transmittal for purposesof security and network diagnostics, and can report security and networkdiagnostics information to the control system through the network.

The monitoring circuit 124 also associates each I/O channel 118 with anetwork address that uniquely identifies the I/O channel and associatesthe port 114 MAC address with that network address. The monitoringcircuit tags the data received from a conversion circuit with the IPaddress of the I/O channel and distributes data received through theport 114 to the proper I/O channel based on IP address.

The multi-channel I/O network module 102 enables a single network portto connect multiple field devices to the network such that the controlsystem interacts with the field devices as if each field device wereindependently connected to the network.

The illustrated network port 114 of the multi-channel I/O network module102 has one port MAC address 116 but functions as a network switchhaving multiple IP addresses and/or MAC addresses behind the switchassociated with the port MAC address. A controller on the processcontrol network could write all data for field devices attached to theI/O network module 102 to the single MAC address of the network port andthe network port then functions as a switch conveying the data to thecorrect field device. The controller in possible embodiments would nothave knowledge of MAC addresses behind the network switch 114, eventhough each I/O channel 118 in embodiments would have its own MACaddress associated with its own network IP address.

Embodiments of the single-channel I/O network module and multi-channelI/O network module can utilize fixed-mode conversion circuits, eliminateinterposer capability by hardwiring signal processing or pass-through inan I/O channel, and can utilize wireless ports instead of, or inaddition to, wired ports.

FIG. 3 illustrates a wired, a wireless, or part wired-part wirelessEthernet-based process control network N that includes single-channelI/O network modules 10 and multi-channel I/O network modules 102 tointerconnect field devices D remote from the I/O network modules to acontrol system S (to simplify the drawing no network hub or switches areshown). Each field device D and the control system S is identified usinga static, unique IPv4 network address A (IPv6 or othernetwork-compatible addressing protocol can be used in other processcontrol network embodiments). Dynamic IP addressing of I/O networkmodules using DHCP or other dynamic network addressing protocols is alsopossible.

No hierarchical network structure is required of the network, and eachdevice can have a communication path to all other devices. Networkswitches and hubs can be used in the network as needed to interconnectthe control system and field devices with one another or to othernetworks via, for example, network gateways or the Cloud.

Network topologies can be formed for enhanced security and networkreliability. For example, a ring topology can be used for networkredundancy. Field wire terminations can be physically distributed ormoved throughout the physical plant without impacting the logicalnetwork connections between field devices. Network connections can alsobe extended to the “Cloud” for connection of the control system andfield devices to remote network resources.

Other examples of electrical connectors that can be used to land wiresof a field device in embodiments of single-field device I/O connectorsor multi-field device I/O connectors in accordance with this disclosureinclude, but are not limited to, pluggable wire connectors in which thewires terminate on the electrical connectors, fixed terminals in whichthe wires enter terminals fixed directly on the base, electricalconnectors that are removably mounted on the base to enable mechanicaland/or electrical disconnection of the electrical connectors from thebase without disturbing field wire attachments to the electricalconnectors, male or female electrical connectors that mate withcorresponding female or male electrical connectors attached to andforming part of individual field wires, cable connectors for connectinga cable containing the field wires extending from the field device, andthe like.

While one or more embodiments are disclosed and described, it isunderstood that this is capable of modification and that the scope ofthe disclosure is not limited to the precise details set forth butincludes modifications obvious to a person of ordinary skill inpossession of this disclosure, including (but not limited to) changes inmaterial selection, network topology, network data and addressingprotocols, network physical layer and type or number of network ports(including wireless network ports for connecting to wireless processcontrol networks), types or numbers of electrical connectors forconnecting field wires of a field device (for non-limiting examples oftypes, terminals or cable connectors), and also such changes andalterations as fall within the purview of the disclosure and thefollowing claims.

What is claimed is:
 1. An I/O network module for a digital processcontrol network, the I/O network module comprising: a base mounting aset of electrical connectors, an I/O channel, and a network port, theset of electrical connectors comprising at least one electricalconnector; the network port compatible with the process control networkfor attaching the I/O network module to the process control network; theset of electrical connectors being connectable with field wiresextending from a field device to carry I/O signals between the set ofelectrical connectors and the field device; the I/O channel includingthe set of electrical connectors and extending to the network port tocarry signals between the network port and the set of electricalconnectors, the I/O channel comprising a conversion circuit configuredto convert between I/O signals and a digital signal compatible with theprocess control network; and the network port being associated with aunique network address when the I/O network module is attached to theprocess control network whereby the I/O network module can communicateover the process control network using the network address.
 2. The I/Onetwork module of claim 1 wherein the conversion circuit is aselectable-mode conversion circuit.
 3. The I/O network module of claim 1wherein the network port is an Ethernet-compatible network portassociated with a MAC address.
 4. The I/O network module of claim 3wherein the conversion circuit is configured to convert between I/Osignals and one of the following formats: Ethernet/IP and OPC UA.
 5. TheI/O network module of claim 1 wherein the network address is a TCP/IPIPv4 or TCP/IP IPv6 network address.
 6. The I/O network module of claim1 wherein the network address is a static network address when the I/Onetwork module is attached to the process control network.
 7. The I/Onetwork module of claim 1 wherein the network address is a dynamicnetwork address obtained when the I/O network module is attached to theprocess control network.
 8. The I/O network module of claim 1 whereinthe network port has a MAC address.
 9. The I/O network module of claim 1comprising an I/O module removably attached to the base that defines aportion of the I/O channel.
 10. The I/O network module of claim 1wherein the I/O network module is a single-channel I/O network module.11. The I/O network module of claim 1 wherein the I/O network module isa multi-channel I/O network module wherein the set of electricalconnectors is a first set of a plurality of sets of electricalconnectors and the I/O channel is a first I/O channel of a plurality ofI/O channels, each I/O channel extending from a respective set ofelectrical connectors to the network port, and each I/O channelconfigured to be associated with a unique network address.
 12. The I/Onetwork module of claim 11 comprising a terminal block that comprisesthe plurality of electrical connectors.
 13. The I/O network module ofclaim 11 wherein the plurality of I/O channels includes a commonmonitoring circuit disposed between the conversion circuits and thenetwork port, the monitoring circuit being configured to route digitaldata received from the conversion circuits to the network port and toroute digital data received from the network port associated with afield device attached to the I/O network module to the I/O channelconnected to the field device.
 14. The I/O network module of claim 11wherein the network port functions as a network switch that selectivelyconnects the network port to one of the plurality of I/O channels totransfer data to the one I/O channel based on the network addressassociated with the data received into the network port from the processcontrol network.
 15. A digital process control network comprising: oneor more I/O network modules attached to the process control network;each I/O network module comprising a base comprising a set of electricalconnectors, an I/O channel, and a network port, the set of electricalconnectors comprising at least one electrical connector, the networkport compatible with the process control network and attached to theprocess control network for communications with the process controlnetwork, the set of electrical connectors being connected to a set offield wires extending from a field device spaced away from the I/Onetwork module to carry I/O signals between the set of electricalconnectors and the field device, and the I/O channel including the setof electrical connectors and extending to the network port to carrysignals between the network port and the set of electrical connectors,the I/O channel comprising a conversion circuit being configured toconvert between I/O signals and a digital signal compatible with theprocess control network, and the I/O channel being associated with aunique network address.
 16. The process control network of claim 15wherein the one or more I/O network modules comprises at least onesingle-channel I/O network module.
 17. The process control network ofclaim 15 wherein the one or more I/O network modules comprises a leastone multi-channel I/O network module wherein the set of electricalconnectors is a first set of a plurality of sets of electricalconnectors and the I/O channel is a first I/O channel of a plurality oflike I/O channels, each I/O channel extending from a respective set ofelectrical connectors to the network port, each set of electricalconnectors connectable to field wires extending from a respective fielddevice spaced away from the multi-channel I/O network module.
 18. Theprocess control network of claim 15 wherein the process control networkis an Ethernet/IP network or an OPC UA network.
 19. The process controlnetwork of claim 15 wherein each network port of the one or more I/Onetwork modules has an IPv4 or IPv6 network address.
 20. The processcontrol network of claim 15 wherein each I/O channel of the one or moreI/O network modules is associated with a unique network address.